Elevation data Image Western Norway 2020 Part 1 of 5

Elevation data provides a detailed description of terrain and surface. The data are established as point clouds from airborne laser scanning or matching from aerial images. The point clouds have varying density (point/m²) for different purposes. From the point clouds, elevation models are generated on grid format of terrain (DTM) and surface (DOM).高程数据（Elevation data）可精细化刻画地形与地表特征。该类数据可通过机载激光扫描（airborne laser scanning）生成点云（point clouds），或通过航空影像（aerial images）匹配获取点云。此类点云的密度（单位：点/平方米，point/m²）会根据不同应用需求有所差异。基于此类点云，可生成格网格式的地形高程模型（数字地形模型DTM，Digital Terrain Model）与地表高程模型（数字正射影像模型DOM，Digital Orthophoto Map）。